Evidence

Methicillin-resistant Staph. aureus

Table 1: Detailed description of each study

# Article Objectives Study Design Main Findings Discussion

O’Sullivan N & Keane  To assess risk factors  Questionnaire.  786 of 910 eligible residents completed the Male sex was identified as

2 CT for MRSA colonization  Setting: Six LTC facilities questionnaire. the most significant

in the nursing home in Ireland.  121 residents were identified as MRSA positive. independent risk factor for

“Risk factors for setting.  Time period: Study  MRSA prevalence varied from 1 to 27% within the MRSA colonization. The

colonization with conducted over 5 months, participating nursing homes. underlying reason for this

methicillin-resistant but exact time period not  Male sex, age > 80, residence in a nursing home for apparent association is

Staphylococcus aureus specified. .05 and the 95% confidence interval included

one, this result was actually not significant.

Terpenning MS et al.  To assess the  Prospective observational  In the first year of the study, colonization rates for Colonization with antibiotic-

4 colonization and study. MRSA, R-ENT, and R-GNB were 22.7 ±1%, 20.2 ± resistant bacteria was

“Colonization and infection with MRSA,  Setting: 120-bed Veteran 1%, and 12.6 ± 1%, respectively. endemic in this patient

infection with antibiotic- high level gentamicin- Affairs LTC facility  In the second year of the study, MRSA colonization population.

resistant bacteria in a resistant entercococci attached to a 300-bed rates decreased to 11.5 ± 1.8% following a

long-term care facility” (R-ENT), and acute care hospital in decolonization intervention with mupirocin. The R-GNB strains

gentamicin and/or Michigan.  Logistic regression analysis revealed the following demonstrated a lower rate of

Journal of the American ceftriaxone-resistant  Time period: June 1989 – associations in terms of colonization: colonization, but a higher rate

Geriatrics Society gram-negative bacilli May 1991.  The presence of wounds (OR: 3.1, 95% CI: 1.8- of infection as compared to

(R-GNB).  Study population: 5.4, p = 0.0001) and decubitus ulcers (OR: 2.7, the MRSA and R-ENT

1994;42(10):1062-69.  Size: N=551. 95% CI: 1.1-6.5, p = 0.027) were independently strains. Therefore, infection

 To identify the factors  Mean age: 64.4 ± 0.5 associated with MRSA colonization. control programs should

associated with years.  The presence of wounds (OR: 2.6, 95% CI: 1.7- target the risk factors

colonization and  Gender: 98.4% male. 3.9, p = 0.0001), renal failure (OR: 2.4, 95% CI: associated with R-GNB

infection with these 1.4-4.3, p = 0.002), intermittent catheterization infections.

organisms. (OR: 2.4, 95% CI: 1.3-4.3, p = 0.004), poor

functional status (OR: 1.8, 95% CI: 1.3-2.5, p = Decolonization efforts with

0.0001), and low serum albumin (OR: 1.6, 95% mupirocin successfully

CI: 1.1-2.2, p = 0.015) were independently decreased MRSA

associated with R-ENT colonization. colonization rates, but had

 Intermittent catheterization (OR: 3.9, 95% CI: little impact on the overall

2.2-6.9, p = 0.0001), inflammatory bowel infection rate. Additionally, it

disease (OR: 3.4, 95% CI: 1.2-9.9, p = 0.022), lead to the selection of

chronic renal disease (OR: 2.7, 95% CI: 1.1-6.8, mupirocin resistant MRSA

p = 0.035), presence of wounds (OR: 1.9, 95% strains. Accordingly,

CI: 1.2-3.0, p = 0.008), and prior pneumonia targeted decolonization,

(OR: 1.9, 95% CI: 1.0-3.6, p = 0.004) were aimed at only high risk

independently associated with R-GNB patients may be a more

colonization. prudent approach.

 Diabetes and peripheral vascular disease were risk

factors for MRSA infection.

 Foley catheters and intermittent catheterization

were risk factors for R-GNB infection.

 The most common types of infections were UTIs

(42.9%) and skin/soft tissue infections (31.9%).

 Almost half (49.6%) of infections with an identified

etiology were due to antibiotic-resistant pathogens.

# Article Objectives Study Design Main Findings Discussion

 Infections were more likely to be caused by R-

GNB than by MRSA or R-ENT.

Hsu CCS  To study the natural  Prospective cohort study.  994 nasal cultures were collected over the study The researchers found that

5 course of MRSA nasal  Setting: 150-bed period. MRSA carriage occurred

“Serial survey of carriage in a nursing community nursing home  86 (8.7%) of those were MRSA positive. most frequently in bedridden

methicillin-resistant home setting. in southern Chicago.  Of the MRSA positive cultures, 4 were from the first patients who also had

st

Staphylococcus aureus  1 floor residents were floor, 51 were from the second floor, and 31 from decubitus ulcers and/or

nasal carriage among ambulatory. the third floor. foreign bodies (i.e., feeding

nd

residents in a nursing  2 floor residents were 

st nd rd

MRSA prevalence on the 1 , 2 , and 3 floors tubes, catheters) in place.

home” generally debilitated were 3.4%, 15.7%, and 9.4%, respectively. Their results indicated that

and required skilled  On average, 35.3% of residents surveyed had debility is a potential risk

Infection Control and nursing care. positive MRSA carriage. factor for MRSA colonization

rd

Hospital Epidemiology  3 floor residents were  Roommate to roommate transmission of MRSA among LTC residents.

generally mentally ill. occurred in only 4 of 19 cases.

1991;12(7):416-21.  Time period: 8 serial  Debilitated patients had a significantly higher MRSA transmission between

surveys were conducted incidence of MRSA carriage (p < 0.001). roommates was infrequent.

over a 15-month The authors suggested that

 Prior hospitalization and antibiotic use were not

timeframe between this might be due to the fact

significantly associated with MRSA carriage.

August 1988 and that there was little direct

November 1989. contact between roommates.

 Study population:

 Size: varied between A more complete

117 to 129 residents demographic picture of the

per survey. study participants would aid

in determining the

generalizability of the results.

Additionally, there may have

been a certain amount of

selection bias present since

6.2% to 12.9% of the

residents either refused or

missed the surveys.

# Article Objectives Study Design Main Findings Discussion



Muder RR et al.  To determine the  Prospective cohort study.  Patients on the intermediate care unit were more This study identified

6 natural history of MRSA  Setting: 432-bed LTC likely to be receiving dialysis (p < 0.001) and to persistent MRSA colonization

“Methicillin-resistant colonization in a LTC Veterans Affairs Medical have chronic obstructive lung disease (p = 0.01) and dialysis as significant risk

Staphylococcal facility. Center in Pennsylvania. compared to those on the nursing home care units. factors for the development

colonization and  To determine if MRSA  Time period: January  981 surveillance cultures were obtained throughout of MRSA infection.

infection in a long-term colonization was 1986 to December 1988. the study period.

care facility” predictive of infection.  129 (13.1%) were MRSA positive. Patients colonized with

Study population:  32 patients were persistent carriers of MRSA. MRSA were almost four

Annals of Internal  Intermediate care  MRSA carriers were more likely to reside on times more likely to develop

Medicine patients: the intermediate care unit. infection than those colonized

 Size: N=99.  MRSA carriers were more likely to develop with methicillin-sensitive

1991;114(2):107-12.  Mean age: 64.8  14 staphylococcal infection than non-carriers or strains.

years. patients colonized with methicillin-sensitive S.

aureus (RR: 3.8, 95% CI: 2.0-6.4, p < 0.01). The authors noted that the

 Nursing home care unit  There was a 15% increased risk of infection for use of nasal cultures as the

patients: every 100 days of MRSA carriage. sole screening method might

 Size: N=97.  Multivariate analysis revealed that persistent have caused them to miss

 Mean age: 64.8  13 MRSA carriage (OR: 3.7, p < 0.001) and dialysis colonization of other body

years. (OR: 2.8, p < 0.005) were significant predictors of sites. Nevertheless, they

MRSA infection. concluded that “the finding of

persistent colonization of the

nares predicted 73% of all

MRSA infections” in their

patient population.

# Article Objectives Study Design Main Findings Discussion



Kauffman CA et al.  To assess the effect of  Prospective surveillance  89 of 321 patients (27.7%) were colonized with Although mupirocin therapy

12 mupirocin therapy on study. MRSA; 65 ultimately received mupirocin therapy. quickly eliminated MRSA

“Attempts to eradicate the colonization,  Setting: 120-bed Veteran  2 refused treatment. colonization, there was a high

methicillin-resistant transmission, and Affairs LTC facility.  12 were transferred, discharged, or died prior recurrence rate among study

Staphylococcus aureus infection rates of MRSA attached to a 300-bed to beginning therapy. participants. Notably, the

from a long-term-care in a LTC facility. acute care hospital in  10 received less than 2 weeks of therapy prior application of mupirocin to

facility with the use of  To determine if Michigan. to discharge or death. the nares alone was not

mupirocin ointment” maintenance therapy  Time period: June 1990 to  In the first 6 months of the study, 40 of 48 (83.3%) sufficient to decrease overall

with mupirocin June 1991. of patients were cleared of nasal MRSA carriage. colonization rates.

American Journal of contributed to the  Study population:  In the second 5 months, when both nares and Additionally, the therapy did

Medicine development of  Size: N = 65*. wounds were treated, 18 of 19 (94.7%) of patients not have a significant effect

mupirocin-resistant  Mean age: 64.2  1.5 were cleared of MRSA carriage. on MRSA infection rates.

strains. years.  18 of 48 (37.5%) of patients had at least one MRSA

1993;94(4):371-78.  63 male; 2 female. recurrence during the initial 7 months of the study; 8 The authors concluded that

 Topical mupirocin 2% was of 17 (47.1%) had a recurrence in the second 5 the costs of ongoing

applied to the anterior months. surveillance, the lack of

nares and/or colonized  The mean monthly MRSA colonization rate benefit in decreasing

wounds of MRSA positive decreased from 22.7%  1.0% to 11.5%  1.8% (p infection rates, and the

patients. = .0001) when mupirocin was applied to the nares potential for selecting

and wounds. mupirocin-resistant

 Treatment of the nares alone did not significantly organisms preclude the

*This number represents the affect colonization rates. chronic use of mupirocin for

MRSA decolonization.

total number of patients that  Mupirocin therapy did not significantly affect MRSA

received mupirocin therapy. Rather, they recommended

infection rates.

However, initial surveillance reserving its use for outbreak

cultures were performed on 321  Mupirocin-resistant strains were isolated in 7 of 65

situations.

patients. (10.8%) MRSA colonized patients.

Potential study limitations

included the small sample

size and the fact that most of

the participants were male

and self-selected.

# Article Objectives Study Design Main Findings Discussion



Strausbaugh LJ et al.  To evaluate the effects  Prospective observational  10 (58%) patients in Group I, 4 (67%) patients in This study, though small,

13 of decolonization study. Group II, and 6 (46%) patients in Group 3 had reinforces the argument

“Antimicrobial therapy therapy on MRSA  Setting: 120-bed Veteran persistent or recurrent MRSA colonization despite against routine MRSA

for methicillin-resistant colonized patients. Affairs skilled nursing receiving antimicrobial therapy. decolonization strategies.

Staphylococcus aureus  To assess the role of facility in Vancouver,  Decolonization efforts were more effective among

colonization in residents the nursing home Washington. the nursing staff; 6 of 7 nurses had negative MRSA The researchers found that

and staff of a Veterans environment as a  Time period: April 1996. cultures following rifampin therapy. antimicrobial therapy was

Affairs nursing home potential reservoir for  Study population:  Following the decolonization program, rifampin “ineffective” and “potentially

care unit” MRSA.  Size: N=43 (36 male susceptibility decreased from 92% to 43%, hazardous.”

patients, 7 nurses). clindamycin susceptibility decreased from 89% to

Infection Control and  Mean age: 77 years. 61%, and TMP-SMX susceptibility decreased from “Decolonization therapy

Hospital Epidemiology 100% to 95%. should not be employed in

 Patients and staff were nursing home settings unless

1992;13(3):151-59. divided into 3 treatment patient-to-patient contact can

groups: be minimized or eliminated,

 Group I: nasal MRSA and even then, the ability of

colonization only the current regimens to

(N=17 patients, 7 eliminate the carrier state in

staff). this population must be

considered uncertain.”

 Group II: nasal MRSA

colonization at nasal or One major methodological

other site, no foreign drawback was the

bodies (N=6). researchers’ use of several

different antibiotic regimens.

 Group III: MRSA The number of patients on

colonization at nasal or each regimen was too small

other site and to make any meaningful

presence of foreign comparisons in terms of

body (N=13). treatment efficacy. However,

according to the authors,

 Decolonization therapy MRSA persistence or

consisted of rifampin, recurrence was seen with

trimethoprim- virtually all regimens.

sulfamethoxazole (TMP-

SMX), clindamycin, or

some combination of the

# Article Objectives Study Design Main Findings Discussion

three.

Table 2: Guideline, Recommendation or Review

# Article Guidelines or Recommendations

Sioux Falls Task Force on Antimicrobial Resistance  This report attempts to identify prevention and control

1 strategies for limiting MRSA transmission in the LTC

“Guidelines for the prevention and control of methicillin- setting. It incorporates recommendations from the

resistant Staphylococcus aureus in long-term care SHEA position paper described below.

facilities”

 It covers the following areas as they relate to MRSA:

South Dakota Journal of Medicine  Epidemiology.

 Goals of infection control.

1999;52(7):235-40.  Surveillance, prevention and control measures.





Simor AE  This article provides a review of the epidemiology

7 and risk factors of MRSA. It also outlines common

“Containing methicillin-resistant S aureus: diagnostic and management techniques as well as

Surveillance, control, and treatment methods” current treatment recommendations.



Postgraduate Medicine



2001;110(4):43-48.



Centers for Disease Control and Prevention  This fact sheet covers main points related to the

8 detection, screening and susceptibility testing of

“Fact Sheet: Laboratory Detection of MRSA in the clinical laboratory.

Oxacillin/methicillin-resistant Staphylococcus Aureus”



Available at:

http://www.cdc.gov/ncidod/hip/Lab/FactSheet/mrsa.htm



1999.



Mulligan ME et al.  This review presents a consensus approach to the

9 management and control of MRSA.

“Methicillin-resistant Staphylococcus aureus: A  In provides a review of the microbiology,

consensus review of the microbiology, pathogenesis, pathogenesis, and epidemiology of MRSA.

and epidemiology with implications for prevention and  Additionally, it covers indications for antimicrobial

management” therapy and control strategies for specific settings

(including LTC).

American Journal of Medicine



1993;94(3):313-28.



Bradley SF  This article tries to address some of the problems

10 associated with managing MRSA in the nursing

“Methicillin-resistant Staphylococcus aureus in nursing home setting.

homes”  It covers the following topic areas:

 Prevalence.

Drugs and Aging  Risk factors.

 Treatment considerations.

1997;10(3):185-98.  Infection control strategies.

 Outbreak management.



Strausbaugh LJ et al.  This position paper from the Society for Healthcare

11 Epidemiologyof America (SHEA) highlights the

“SHEA Position Paper: Antimicrobial resistance in growing problem of antimicrobial resistance in LTC

long-term-care facilities” facilties. Additionally, it provides recommendations

for control strategies and identifies priorities for future

Infection Control and Hospital Epidemiology research.



1996;17(2):129-40.